Song pairs in rock music

Back in the days of FM radio, there were some songs by certain artists that the DJs would always play back-to-back, usually because there was no space between them on the LP. As a result, if I hear one song without the other, it feels like there's something missing. Here are some examples:
"Feeling That Way"/"Anytime" - Journey
"Heartbreaker"/"Living Loving Maid (She's Just A Woman)" - Led Zeppelin
"Waitin' For the Bus"/"Jesus Just Left Chicago" - ZZ Top